And as well as babysitting themselves, 23% of grandparents also say they pay for babysitters so everyone can have a break.

Baroness Sally Greengross, president and chief executive of ILC-UK, said: "It is clear grandparents have become one of the biggest sources of childcare after parents themselves, allowing more parents to work and thereby reducing the costs of childcare.

"Nevertheless, how we support and reward this growing unpaid army and how we reconcile an increasing need to work longer for the over 50s, 60s and 70s and shape and expand family friendly policies for all, remains subject to debate."

* More than 2,000 people were surveyed for the Ageas and ILC-UK report, which used average childminder costs as a base for its calculations.